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Too Hot In Vehicle (Auxiliary)

WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit reference, see CONNECTOR IDENTIFICATION  and/or WIRING DIAGRAMS  .
NOTE: Definition: Auxiliary air temperature can not be adjusted from one or both auxiliary controls or auxiliary cooling is insufficient.
  1. Did you review DESCRIPTION & OPERATION and perform the necessary inspections? If so, go to next step. If not, see DESCRIPTION , OPERATION  and TROUBLE SHOOTING  .
    2. NOTE: The auxiliary A/C system cannot request A/C compressor operation. The mode switch must be positioned to MAX, NORM, BI-LEVEL, BLEND or DEFROST on the HVAC control module to provide cooled airflow through the auxiliary system.
  2. Does the HVAC control module operate and provide sufficient cooling? If so, go to next step. If not, see TOO HOT IN VEHICLE .
  3. Turn ignition on. Place the heat and/or A/C auxiliary blower motor switch in each speed position. Does the auxiliary blower motor operate at all? If so, go to next step. If not, see AUXILIARY BLOWER MOTOR INOPERATIVE (A/C OR HEATER) .
  4. Does the auxiliary blower motor operate correctly for each speed position? If so, go to next step. If not, see AUXILIARY BLOWER MOTOR MALFUNCTIONS (A/C OR HEATER) .
  5. Is the vehicle equipped with an auxiliary heating system? If so, go to next step. If not, go to step  7.
  6. Start the engine. Place the auxiliary heater blower motor switch in the OFF position. Run the engine to achieve normal operating temperature. Are the auxiliary heater hoses or auxiliary heater core hot? If so, go to step  8. If not, go to next step.
  7. Perform the refrigerant system performance test. See A/C PERFORMANCE TEST  under PERFORMANCE TESTS. Did you find and correct the condition? If so, go to step  15. If not, go to next step.
  8. Disconnect the vacuum hose from the auxiliary coolant bypass valve. Is there vacuum present at the auxiliary coolant bypass valve vacuum hose? If so, go to next step. If not, go to step  11.
  9. Turn ignition off. Disconnect the coolant bypass valve solenoid. Connect a test light between ground and the control circuit of the coolant bypass valve solenoid. Turn ignition on. Place the auxiliary heater blower motor switch in the OFF position. Does the test light illuminate? If so, go to next step. If not, go to step  11.
  10. Check the control circuit of the coolant bypass valve solenoid for a short to voltage. Did you find and correct the condition? If so, go to step  15. If not, go to step  12.
  11. Inspect the harness connector of the auxiliary coolant bypass valve solenoid for poor connections. Did you find and correct the condition? If so, go to step  15. If not, go to step  13.
  12. Inspect the auxiliary heater blower motor switch for poor connections. Did you find and correct the condition? If so, go to step  15. If not, go to step  14.
  13. Replace the auxiliary coolant bypass valve. See COOLANT BYPASS VALVE  in REMOVAL & INSTALLATION. After repairs are complete, go to step  15.
  14. Replace the auxiliary heater blower motor switch. See AUXILIARY BLOWER SWITCHES  in REMOVAL & INSTALLATION. After repairs, go to next step.
  15. Operate the system in order to verify the repair. If system operates normally, repair is complete. If system still malfunctions, return to step  2.
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